Multibarrel automatic weapon

ABSTRACT

A gun having at least a barrel, at least a chamber and means for moving said chamber transversely to said barrel from a noncoaxial feed station to a coaxial lock and fire station, and means including a stationary cam surface for progressively chambering a cartridge in said chamber as it moves from said feed station to said lock and fire station.

llnlted States Patent Ashley et a1. Oct. 17, 1972 [54] MULTIBA-RREL AUTOMATIC 2,998,758 9/1961 Quellette ..89/33 R X WEAPON 2,959,106 11/1960 OBrien ..89/33 MC X [72] Inventors: Eugene Ashley, Burlington; Douglas 2856819 10/1958 Meyers et "89/33 MC X P. Tassie St George; James M. 1,424,751 8/1922 Bangerter ..89/155 X S South i g n of Dal'dlCk X Vt. Primary Examiner-Samuel W. Engle [73] Asslgnee: General Elecmc P Y Attorney-Bailin L. Kuch, Harry C. Burgess, Irving M. 22 Filed; March 10, 1970 Freedman, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman [21] Appl. No.: 18,031

V a 9 a [57] ABSTRACT V [52] US. Cl ..89/12, 139/13 R, 89/33 MC A gun having at least a barrel at least a chamber and lift. means for moving Said chamber transversely to i {58] held of Search f barrel from a noncoaxial feed station to a coaxial lock 89,126 2/39'5 and fire station, and means including a stationary cam surface for progressively chambering a cartridge in [56] References cued said chamber as it moves from said feed station to said UNITED STATES PATENTS lock and fire Station- 2,971,440 2/1961 OBrien ..89/33 MC X 4 Claims, 12 Drawing Figures 14 j 98 92 1% 94 200 I; J or. 190 104 7% 62 (Go a c 9 ll I 1 \z 4 208 be 2 l- Zp7' I? 20 [56 3g 1 54 I54 Q 176 157. 3 (7b no 148 {8:378

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V o 2 1 4 232 Z0 21a OCT 1 7 I972 SHEET 1 BF 8 Eugene Ashley Douglas P. Tassie James M. Seemann INVENTOR.

PATENTED B 3.698.283

' SHEET 2 OF 8 Eugene Ashley Douglas P. Tassie James M. Seemann I NVENTOR.

BY/Zw nne/v57 PATENIED N 1 2 3,698,283

sum 3 or 8 Eugene Ashley 2 3$ J Douglas P. Tassie l James M. Seernann INVENTOR.

\ UL M 4 PATENTED BT 11 I912 3.698.283

SHEET 4 0F 8 8 8 Eugene Ashley Douglas P. Tassie James M. Seemann INVENTOR.

PTENTEDnm 17 1912 SHEET 7 BF 8 A 111 P T M S PMENIEB 17 I97? 3, 698,283

sum 8 0F 8 Eugene Ashley Douglas P. Tassie James M. Seemann INVENTOR.

197' TDIQ VE Y MULTIBARREL AUTOMATIC WEAPON BACKGROUND OF THE INVENTION The Invention herein described was made in the course of or under a contract or subcontract thereunder, with the Department of Defense.

1. Field of the Invention This invention relates to automatic weapons having a plurality of barrels mounted for rotation about a common axis and adapted to shoot caseless ammunition.

2. Prior Art The classic revolving battery gun is shown in US. Pat. No. 125,563 issued to Richard J. Gatling on Apr. 9, 1872. This gun had a stationary housing; and a rotor assembly, journaled within the housing, having ten barrels and ten reciprocating bolts. The bolts were cammed by the housing and their function was responsive to the angular rotation of the rotor assembly. The gun fired cased ammunition, which was chambered, fired, and ejected by the bolt assembly. The first modern version of the Gatling gun is shown in US. Pat. No. 2,849,921 issued to Harold McC. Otto on Sept. 2, 1958, and a more recent version is shown in U.S. Pat. No. 3,380,343 issued to Robert E. Chiabrandy et al. on Apr. 30, 1968. Each of these modern guns is similar to the classic gun in having pluralities of barrels, chambers and bolts to shoot cased ammunition.

In cased ammunition the case serves, inter alia, two functions, viz: it provides a seal at the aft end of the chamber; and it provides a handle on the round of ammunition for ejection in the event of a misfire. However, the case amounts to some 40 percent of the weight of the round, which if saved, would provide a responsive decrease in system weight, or would provide that much more ammunition storage capacity.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an automatic gun having a high rate of fire of caseless ammunition.

A particular object of this invention is to provide a gun which does not utilize a reciprocating bolt to chamber and lock a cartridge.

A feature of this invention is the provision of a gun having at least a barrel, at least a chamber and means for moving said chamber transversely to said barrel from a noncoaxial feed station to a coaxial lock and fire station, and means including a stationary cam surface for progressively chambering a cartridge in said chamber as it moves from said feed station to said lock and fire station.

BRIEF DESCRIPTION OF THE DRAWING These and other objects, features and advantages will be apparent from the following specification thereof taken in conjunction with the accompanying drawing in which:

FIG. 1 is a perspective view from an aft viewpoint of a weapon embodying this invention;

FIG. 2 is a perspective view from a forward viewpoint of the weapon of FIG. 1;

FIG. 3 is a side elevated view, in cross-section, of the weapon of FIG. 1;

FIG. 4 is a top plan view of the weapon of FIG. 1;

FIG. 5 is an aft end view of the weapon of FIG. 1;

FIG. 6 is an aft end view in cross-section taken along the plane VI-VI of FIG. 3, particularly illustrating the chain of chambers;

FIG. 7 is a forward end view in cross-section taken along the plane VII-VII of FIG. 3, particularly illustrating the misfire conveyor; and

FIGS. 8 and 9 are detail perspective views of the misfire conveyor,

FIG. 10 is a diagram of FIG. 6 for an eight chamber gun,

FIG. 1 1 is a diagram of a second embodiment, similar to FIG. 6, for a ten chamber gun, and

FIG. 12 is a broken view of the weapon of FIG. 1.

THE PREFERRED EMBODIMENT The weapon shown in FIG. 1 is a variant of the classic Gatling principle, and uses a rotating cluster of barrels which is secured in a rotor assembly and is driven by an external power source. Conventional, reciprocating bolts are not employed. Instead, a series of linked tubular firing chambers transport the cartridges into the rotor. In the firing position each chamber rests in a respective deep recess in the rotor and is longitudinally secured or locked between the barrel breech face and a surface of the rotor recess. The chambers are swung out of the rotor recess for loading fresh cartridges, and for ejecting such misfires as occur. This is accomplished by using more chambers than barrels, e.g., a loop of eight or more chambers for a cluster of six barrels. Since the length of the loop is thus longer than the circumference of the pitch circle of the barrel cluster, the loop extends free of the rotor for a portion of its travel and is open for loading and chambering by a stationary cam. The chamber then moves laterally into lock position and firing can thereupon take place. There is no need for a structural locking operation. The fore and aft components of the firing pressure pulse are reacted directly into the rotor structure, and the lateral components are contained by hoop tension in the wall of the chamber.

The housing assembly 10 includes an aft housing 12 and a forward housing 14. The aft housing has a rabbet 16 which receives a lip 18 on the transverse wall 19 of the forward housing for longitudinal alignment. Radial alignment and clamping are provided by a plurality of mating bolt holes and bolts, not shown. A bearing block 20 extends forwardly from the wall 19, and together with a rib 21, supports the misfire ejection assembly 22. A pair of recoil attenuator assemblies 23 are also housed in the forward housing 14. Each recoil attenuator assembly, as best seen in FIG. 4, includes a spindle 24 disposed in a bore 26 through an enlargement in the housing. The forward end of the spindle extends into a clevis 28 of the gun mount and is retained by a pivot bolt 30. An aft external bushing 32 is adjustably threaded into the bore 26, and has a shoulder 34 to retain the aft end of an aft internal bushing 36. A multielement, friction damped spring 38 is captured between the bushing 36 and a forward washer 39 which bears against a shoulder 40 on the spindle, and a shoulder 42 in the housing bore. Compression of the spring is adjusted by a nut 44 hearing against the bushing 36 and threaded on a stud 46 which is threaded into the aft end of the spindle 24.

The feeder assembly 50 is also housed in the aft housing 12. The feeder assembly includes a drive shaft 52 which is journaled through bearing blocks 54 and coupled to a knife blade clutch assembly 56. A pair of four toothed sprockets 58 are fixed to the shaft to positively advance rounds, coming down along and between a pair of guides 60, through an opening 62 in the housing. The clutch assembly 56 may be of the type shown in US. Patent application, Ser. No. 386,656 filed Oct. 1, 1969 by L. K. Wetzel and assigned to a common assignee.

A rotor assembly 70 is journaled for rotation in the housing. The rotor assembly includes a main rotor 72 which has a central, longitudinal bore 74 and six longitudinal bores 76 in an annular row. Six gun barrels 78 are respectively mounted in the bores 76 and secured to the rotor by suitable means, not shown, such as interrupted threads. The rotor is journaled to the forward housing by a pair of annular ball bearing assemblies 80 which is secured by a retaining ring 81. A forward ring gear 82 is captured onto and between the gun barrels and the rotor. A mediate clamp 84 clamps the barrels together and is journaled by a ring bearing 86 to a forward gun mount ring 88. A forward clamp 90 clamps the forward ends of the gun barrels.

The aft portion of the rotor 72 has six recesses 100, each coaxial with a respective gun barrel and having a forward transverse face 102 and an aft transverse face 104. The aft ends 106 of the barrels have respective inserts 108 fixed thereto which project slightly aft of the face 102. A ring gear 110 is fixed to and is coaxial with the aft end of the rotor. The gear has a peripheral annulus of centrifugally directed teeth 112, and an aft, longitudinally extending annulus of six cam ramp surfaces 1 14.

A retaining fastener 116 which is used to longitudinally secure the gear to the rotor comprises a formed rectangular wire ring. The ring takes a G-shape with the distal ends of both legs turning centrifugally from the circumference The ring has a diametral clearance fit around a circumferential groove in the hub of the gear. The legs of the ring protrude through a slot in the hub so that they can be reached through the center hole of the gear. The outside diameter of the ring, when the ring is unconstrained, is slightly larger than the outside diameter of the hub. When the legs of the ring are squeezed together, accessible through the center hole, the ring contracts to an outside diameter equal to or less than the diameter of the hub. The hub can then be inserted into the rotor bore 74 which contains a groove to accommodate the ring when it is unconstrained. When the hub is assembled and the legs are released, the ring is disposed in part in each groove, locking the hub longitudinally.

Six firing pin assemblies 120 are mounted in the aft end of the rotor 72. Each assembly is disposed in a respective bore 120 which is coaxial with a respective gun barrel, and includes a body 124 having a stem portion 126 press fitted into the bore and a head portion 128. The body has a central bore 130 with an internal neck 132. A spindle 134 rides in the bore 130 and has a forward flange 136 and an aft spool 138. A compression spring 140 is disposed on the spindle between the bore neck 132 and the spindle spool 138 to bias the spindle aft, that is, to retract the firing pin. A fixed retraction blade 142 is fixed to the aft housing to insure the retraction of the spool 138, by camming rearwardly any unretracted spool.

Each of the six firing pins is struck in sequence by a single, spring loaded hammer assembly 144. The assembly includes a rod 146 mounted through and between two bearing blocks 148 and 150 which extend outwardly from the aft housing. A support block 152 is fixed at its lower end to the forward end of the rod 146 and at its upper end to one end of a lateral rod 154 whose other end is adjustably fixed to the housing, by two nuts 155, whereby to preclude rotation of the rod 146. A hammer arm 156 pivotally mounted at its lower end to a clevis on the block 152 by a pin 158. The upper end of the arm is formed as a clevis 160, and below the clevis has an integral, forward facing hammer block 162, and therebelow, a forward facing cam follower 164. A plunger 166 has a forward end pivotally mounted to the clevis by a pin 168, an intermediate collar 170, and an aft spindle 172. The aft end of the spindle rides in a diametral bore through a dowel 174 which is mounted in a lateralbore through a toggle bracket 176. The bracket has an aft clevis 178 pivotally mounted to the rod 146 by a pin 180, and a forward clevis 182 mounted to the rod 146 by a pin 184. A compression spring 186 is mounted on the spindle 172 between the collar and the bracket 176. The cam follower 164 rides on each of the cam ramps 114 to compress the spring 186 which is preloaded. The hammer assembly may be safed by extracting the pin 184 and swinging the toggle bracket 176 aft about the pin 180, to preclude any effective compression of the spring 174. The hammer assembly may be armed and the spring 174 preloaded by swinging the toggle bracket 176 forward and inserting the pin 184.

Each of the eight chambers 190 is formed as a tube having a pair of longitudinally distal lugs 192 at one end and a pair of longitudinally set back lugs 194 at the other end. The tubes are alternated end for end so that a lug 192 can overlap the next adjacent lug 194. Each lug has a longitudinal bore therethrough which receives a respective bushing, and adjacent lugs are linked by respective rods 196 each having a forward roller 198 and an aft roller 200. A forward ring seal 202 is disposed in a recess 204 in the forward end of the chamber and an aft ring seal 206 is disposed in a recess 208 in the aft end of the chamber.

A forward cam plate 210 and an aft cam plate 212 are respectively disposed in a forward channel 214 and an aft channel 216 in the rear housing, and are pinned in place. When the rotor is in place, the plates must be unpinned from the rear housing before the housing can be removed. The rear cam plate may be removed once the rear housing has been detached. The front cam plate can be removed after the chambers 190 have been removed. Two holes 218 in the upper portion of the rear cam plate can be utilized for longitudinal withdrawal of any two adjacent rods 196 to permit the removal of the contained chamber, as for inspection of the chamber seals. The cam plates 210,212 have respective cam tracks 220, 222 for respectively supporting the rollers 198, 200 for guiding the chambers 190 through the transition between the upper and lower portion of the loop, and around the lower portion. In the upper portion of the loop each chamber is disposed in and carried by a respective recess 100 in the rotor. Each chamber has two lines of contact 201 with the recess wall profile. This assists in the accurate alignment of the chamber and the respective barrel bore, and provides a clearance space at the bottom of the recess for the accumulation of foreign matter which might otherwise disturb the chamber position.

As shown in FIGS. 6 and 10, the barrels and the rotor 72 revolve about a longitudinal axis A. The chain of chambers 190 is carried around by the rotor 72 serving as a six tooth sprocket, and is guided around a virtual six tooth sprocket having a longitudinal axis B. The transverse distance between the axes A and B is equal to the transverse distance between the axes of adjacent shafts 196, i.e., the link length. The transverse distance between the axes A and B is also equal to the transverse distance between the axis A and the axis of the shaft 196 of any chamber engaged with the rotor 72, and is also equal to the transverse distance between the axis B and axis of the shaft 196 of any chamber effectively carried around the virtual sprocket. The virtual sprocket, as shown, can not be realized since it would then overlap in volume the real sprocket 72. However, the effect of the sprocket is provided by the cam tracks 220,222 which guide the rollers on the shafts, and, thereby, the chambers through the cusp transitions between the sprockets and around the virtual sprocket. No cam tracks are provided around the upper semicircle 72 as the rollers 198, 200 ride on the sprocket. It may be noted that by locating the axes of the shafts 196 external to the rotor, relatively deep recesses 100, with relatively thick distal rib sections therebetween, can be provided. Shouid it be desired to realize the virtual sprocket and/or to increase the number of chambers in the chain, as shown in FIG. 1 1, it is merely necessary to make the transverse distance between the axes of the rotors a multiple of the link length, and to add one additional cam track cusp for each additional link length. For example, ten chambers can be accomodated around and between two rotors whose rotors axes are spaced apart by two link lengths, and provided with cam tracks having two cusps per side. The use of the cusps is necessary to maintain the rotor inter axis spacing constant during movement of the chain of chambers around the rotors.

The forward and aft cam plates also serve to retain the chamber seals in the respective chambers during the feed cycle when these chambers are in the lower portion of the loop. The forward cam plate also serves as a fixed stop and has an elastomeric shock absorbing surface adjacent the end of an ejection slot 224 in the lower portion of this plate to halt newly chambered rounds flush with the forward end of the respective chamber.

Rounds handed into the gun by the feeder assembly 50 are chambered by a rotary feed tray 230 and a stationary ram cam 232. A back plate 234 is fixed to the aft end of the aft housing. A longitudinal support rod 236 is fixed to the back plate. The rotary feed tray 230 has six longitudinal recesses 235, each for receiving a cartridge, and is journaled on the rod 136 by a forward bearing 238 and an aft bearing 240. An annular spur gear 242 is coaxial with and fixed to the aft end of the tray 230. A shaft 244 is journaled to the aft housing, has a forward spur gear 246 fixed thereto and meshed with and driven by the rotor spur gear 112, and has an aft spur gear 248 fixed thereto and meshed with and driving the tray gear 242 through an aperture in the housing. A spur gear 250 of the feeder assembly clutch 50 is also meshed with and is driven by the tray gear 242. The stationary ram cam 232 is a lateral section of a tube and has a cycloidal cam slot 252 having a forwardly sloping shoulder 254 which extends around the complete ram are at the bottom of the housing and slopes forward one full round length.

Gun action may be considered to start with a cartridge in the feeder sprocket 58. The feed tray 230 rotates in synchronization with the loop of chambers 190 and the rotor 72. Depending upon the type of feed system used, the cartridge will have been picked up by the sprocket from a conveyor, or handed in directly from the exit unit of a storage drum. As the feeder sprocket rotates, the cartridge is cammed centrifugally by the side guides until its pitch velocity matches that of the rotary feed tray. Hand off into a recess of the rotary feed tray is thus accomplished without any abrupt change in velocity. After hand off, the cartridge is controlled by the feed tray. Lateral movement of the cartridge is precluded by the contour of the respective recess and the adjacent interior wall of the stationary ram cam 252. The cartridge is carried in coaxial alignment with an empty chamber and is free to move forward longitudinally. Forward ramming begins after the cartridge has been fully captured in the rotary feed tray. As the cartridge is carried around by the rotary feed tray it is also slid along in the stationary ram cam slot 252, whose shoulder 254 abuts the aft end of the cartridge and earns the cartridge longitudinally forward into the chamber. In FIG. 3, cartridge 256 is shown partially chambered. Once chambered, the cartridge remains chambered as the respective chamber moves into its respective rotor recess and is sealed between its respective barrel 78 and firing pin head portion 128. The cycloidal shape of the ram cam accelerates the cartridge uniformly, and allows it to decelerate. as much as possible under the effect of friction before striking the stop. As the chamber passes the firing position the cam follower 164 rides off a respective cam ramp surface 114 and the released compression spring 186 drives the hammer arm 156 forward to impact the firing pin spindle 134 to fire the cartridge. Since the cartridge is caseless and consumable, the chamber is empty after firing and is ready to receive a fresh cartridge. To clear the gun at the end of a burst, the clutch 56 is disengaged to halt the feeder assembly drive shaft while the rotor assembly continues to rotate and fire all chambered cartridges. The gun comes to a full stop with all of its chambers empty.

The gun is designed to utilize a telescoped cartridge having a cylindrical shape without any step or taper. Thus a fresh cartridge incoming aft will displace a misfired cartridge presently in a chamber and force it out forward. No provision need be made for separable extraction of misfired cartridges, and this combining of the feeding and extracting processes greatly simplifies the gun. Room is left ahead of the loading area for a misfired cartridge to clear the housing. As a misfire begins to be ejected from its chamber, it is captured and controlled by a gear driven ejector assembly forward of the chamber, as shown in FIGS. 3,7,8 and 9.

The misfire ejector assembly comprises a worm 260 fixed on a shaft 262 which is journaled to and between the bearing block 26 and the rib 21, and has a mitre gear 264 fixed thereto. A power shaft 266 is journaled to the housing and at its aft end is coupled to a power source, not shown, such as a hydraulic motor. A mitre gear 268 is fixed to the forward end of the shaft and meshed with the worm mitre gear 264. A spur gear 270 is also fixed to the shaft 266 and is meshed with a spur gear 272 fixed on the shaft 244. A pressure roller 274 is mounted to the housing by a spring 276 at an angle to the worm. The worm is provided with a friction surface composed of wire studs embedded in the worm surface and fixed with epoxy.

As the eight chambers rotate around the lower portion of the loop on a six chamber circle past the ejection slot 224 they maintain a spacing of 60 between adjacent chambers. The worm lead is also 60 of profile rotation for one revolution of the worm. Thus the concavity 276 in the worm provides a shape which laterally mates with the cylindrical shape of the cartridge, so that the cartridge remains longitudinally aligned with the bore of the chamber as the chamber progresses along the ejection slot. For each revolution of the rotor the worm is geared to rotate six times, allowing the concavity shape to follow all six chambers.

As a chamber containing a misfired cartridge progresses along the ejection slot, the fresh cartridge then being chambered by the ram cam pushes the misfired cartridge longitudinally forward, from the chamber bore, through the ejection slot, as shown in FIG. 8, into the concavity 276 of the worm, under the spring loaded roller 274. The worm acts as an endless conveyor which supports, cradles and longitudinally stabilizes the cartridge as it is ejected. In addition, the relatively high peripheral speed of the worm accelerates the cartridge out of the chamber and creates a gap between the aft end of the misfired cartridge and the fresh cartridge being chambered. The ejection slot terminates, and the wall of the forward cam plate 210 is accomodated in this gap. The aft surface of the forward cam plate serves to stop the fresh cartridge when it is fully chambered. The spring loaded roller ensures engagement between the misfired cartridge and the worm during gun low speed or hand cycling. Centrifugal force serves this function at relatively higher gun speeds.

To insure clearing of all chambers at the end of a burst of firing, after the declutching operation has occurred,an air blast is provided. Ifa misfire should occur in the last eight rounds chambered prior to declutching, the air blast must serve in lieu of an incoming round to displace the misfire. An air fitting 280 is fitted into a longitudinal blind bore 282 in the support rod 236 which communicates with a radial bore 284 directed downwardly. Six air tubes 286 are disposed in the feed tray 230, each respectively aligned with a recess 235. The air tube for the lowermost recess, which is the chamber-eject position, is in communication with the bore 282. When the burst of firing is to be ended, the supply of cartridges to the feeder assembly 50 is discontinued and a supply of air is delivered to the fitting 280. As the feed tray rotates, a blast of air is delivered successively through each air tube to the respective chambers to blast out any misfired cartridge contained therein.

In a revolving battery gun it is desirable that the ammunition propellant ignite at the twelve oclock position to preclude or at least minimize, lateral torque on the gun mounts. In ammunition having a stab primer there is a significant delay between the time of firing pin impact and propellant ignition. Thus it is necessary to finely adjust the searing of the hammer to preceed the chamber arriving at the twelve oclock position by the delay interval. This adjustment is accomplished by adjusting the effective length of the rod 154, by means of the two nuts 155, to swing the hammer assembly on its pivot rod 146.

While there has been shown and described a preferred embodiment of this invention, it will be appreciated that the invention may be embodied other-.

wise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying idea or principles of this invention within the scope of the appended claims.

What is claimed is: 1. A machine gun comprising: at least a barrel; at least a chamber having a forward end and an aft end and means for moving said chamber transversely to said barrel from a feed station to a lock and fire station which is coaxial with said barrel, and return; means for chambering a cartridge from said aft end forwardly into said chamber as it moves between said feed and fire stations including a housing having a forward plate defining a transverse surface immediately adjacent said forward end of said chamber for directly receiving and halting the newly chambered cartridge flush with said forward end of said chamber;

a stationary cam surface for initially accelerating a cartridge longitudinally and for subsequently permitting significant frictional deceleration of said cartridge before it strikes said transverse surface of said plate; and

a transversely movable feed tray for disposing a cartridge against and along said cam surface for inserting the cartridge into said chamber at said feed station.

2. A machine gun according to claim 1 wherein said transverse surface of said plate includes a portion having an elastomeric shock absorbing surface to directly receive and to halt the newly chambered round flush with said forward end of said chamber.

3. A machine gun comprising:

a plurality of barrels;

a plurality of chambers larger in number than said plurality of barrels, and each chamber having a forward and an aft end,

means for chambering a cartridge;

said means including a housing having a plate defining a transverse surface immediately adjacent said forward end of said respective chamber while a cartridge is being chambered therein, for directly receiving and halting the newly chambered cartridge flush with said forward end of said chamber;

tridge before it strikes said transverse surface. 4. A machine gun according to claim 3 wherein said transverse surface of said plate includes a portion having an elastomeric shock absorbing surface to directly receive and to halt the newly chambered round flush with said forward end of said chamber. 

1. A machine gun comprising: at least a barrel; at least a chamber having a forward end and an aft end and means for moving said chamber transversely to said barrel from a feed station to a lock and fire station which is coaxial with said barrel, and return; means for chambering a cartridge from said aft end forwardly into said chamber as it moves between said feed and fire stations including a housing having a forward plate defining a transverse surface immediately adjacent said forward end of said chamber for directly receiving and halting the newly chambered cartridge flush with said forward end of said chamber; a stationary cam surface for initially accelerating a cartridge longitudinally and for subsequently permitting significant frictional deceleration of said cartridge before it strikes said transverse surface of said plate; and a transversely movable feed tray for disposing a cartridge against and along said cam surface for inserting the cartridge into said chamber at said feed station.
 2. A machine gun according to claim 1 wherein said transverse surface of said plate includes a portion having an elastomeric shock absorbing surface to directly receive and to halt the newly chambered round flush with said forward end of said chamber.
 3. A machine gun comprising: a plurality of barrels; a plurality of chambers larger in number than said plurality of barrels, and each chamber having a forward and an aft end, means for chambering a cartridge; said means including a housing having a plate defining a transverse surface immediately adjacent said forward end of said respective chamber while a cartridge is being chambered therein, for directly receiving and halting the newly chambered cartridge flush with said forward end of said chamber; a transversely movable feed tray for moving each cartridge in sequence transversely, and a stationary cam surface for abutting the cartridges as they are moved transversely by said tray to move them longitudinally into respective chambers by initially accelerating each cartridge and by subsequently permitting significant frictional deceleration of said cartridge before it strikes said tRansverse surface.
 4. A machine gun according to claim 3 wherein said transverse surface of said plate includes a portion having an elastomeric shock absorbing surface to directly receive and to halt the newly chambered round flush with said forward end of said chamber. 